Communication device, control method for communication device, and storage medium

ABSTRACT

A communication device includes a main control part configured to receive and process an image signal; a first network control part configured to convert data input from an external device into the image signal and provide the main control part with the image signal; a sub control part configured to detect a power-on command; and a second network control part configured to control communications with the external device via a network to provide the first network control part with data input from the external device. Power supplies to the main control part, the sub control part, the first network control part and the second network control part are independently controlled.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The disclosures herein generally relate to communication devices,methods for controlling communication devices and storage medium forstoring a program causing the control part of a communication device toexecute a control method.

2. Description of the Related Art

Historically, as disclosed in Japanese Laid-Open Patent Application No.2011-35798, a projector which can communicate with external devices viaa network comprises three microcomputers: an intelligent mainmicrocomputer controlling a graphic processing and optical systemdriving part; a sub microcomputer, which works in a stand-by state,controlling an input unit and a display unit such as an operating paneland a remote controller receiver and an RS-232C terminal; and a networkmicrocomputer controlling a network.

In the stand-by state in which the projector does not project an image,the main microcomputer and the network microcomputer are generallyturned off while only the sub microcomputer is turned on, therebyreducing power consumption.

In addition, Japanese Laid-Open Patent Application No. 2011-35798discloses the following configuration in order to simplify a systemconfiguration and to decrease power consumption. The disclosurecomprises: a main microcomputer and a network microcomputer havingfunctions to control a network, an input unit, and a display unit andfurther having a fan control function. The network microcomputercontrols the power supply to the main microcomputer at the time oftransition to a stand-by state or return to a normal state.

In the configuration using three microcomputers, the networkmicrocomputer has to be switched on in order to use a function usingnetwork communication in stand-by state (e.g. a projector controlfunction with the PJLink protocol). The problem with this arrangement isthat power consumption cannot be reduced sufficiently.

Also on the configuration using two microcomputers, the power of thenetwork microcomputer having various functions needs to be switched onin the stand-by state; this also gives rise to a problem that the powerconsumption cannot be reduced sufficiently. Such a problem occurs notonly in projectors but also in communication devices that have afunction to communicate with an external device via a network. That is,the problem occurs when an attempt is made to reduce power consumptionin the stand-by state in which the network communication function isenabled while other functions are suspended to an extent possible.

This invention aims to solve that problem and reduce power consumptionin the stand-by state in which a network communication function isenabled on a communication device having communication functions with anexternal device via a network.

SUMMARY OF THE INVENTION

It is a general object of at least one embodiment of the presentinvention to provide a communication device and a control method for thedevice that substantially obviates one or more problems caused by thelimitations and disadvantages of the related art.

In one embodiment, a communication device includes:

a main control part configured to receive and process an image signal;

a first network control part configured to convert data input from anexternal device into the image signal and provide the main control partwith the image signal;

a sub control part configured to detect a power-on command; and

a second network control part configured to control communication withthe external device via a network to provide the first network controlpart with data input from the external device;

wherein power supplies to the main control part, the sub control part,the first network control part and the second network control part areindependently controlled.

In another embodiment, a control method is provided to control acommunication device including:

a main control part configured to receive and process an image signal;

a first network control part configured to convert data input from anexternal device into the image signal and provide the main control partwith the image signal;

a sub control part configured to detect a power-on command; and

a second network control part configured to control communication withan external device via a network to provide the first network controlpart with data input from the external device;

wherein power supplies to the main control part, the sub control part,the first network control part and the second network control part areindependently controlled.

The control method includes:

obtaining information about a state of communication with the externaldevice or a configuration for communication with the external devicefrom the second network control part when power supply to the firstnetwork control part or main control part is turned on; and

reporting all or part of the information to a user.

In another embodiment, a computer-readable storage medium for storing aprogram therein is provided. The program causes a communication deviceincluding

a main control part configured to receive and process an image signal;

a first network control part configured to convert data input from anexternal device into the image signal and provide the main control partwith the image signal;

a sub control part configured to detect a power-on command; and

a second network control part configured to control communication withan external device via a network to provide the first network controlpart with data input from the external device;

wherein power supplies to the main control part, the sub control part,the first network control part and the second network control part areindependently controlled

to execute a control method.

The control method includes:

obtaining information about a state of communication with the externaldevice or a configuration for communication with the external devicefrom the second network control part when power supply to the firstnetwork control part or main control part is turned on; and

reporting all or part of the information to a user.

On a communication device having a function to communicate with anexternal device via a network, the configuration stated above may enablethe network communication function even in a stand-by state and reducepower consumption in the stand-by state.

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects and further features of embodiments may become apparentfrom the following detailed description when read in conjunction withthe accompanying drawings, in which:

FIG. 1 is a drawing illustrating a hardware configuration of a projectoraccording to an embodiment of the invention;

FIG. 2 is a functional block diagram of a network CPU described in FIG.1;

FIG. 3 is a table of power supply states prepared in the projector inFIG. 1;

FIG. 4 is a state diagram of the states described in FIG. 3;

FIG. 5 is a flowchart of procedures performed by the sub CPU duringstart up;

FIG. 6 is a flowchart of procedures performed by the network sub CPUduring start up;

FIG. 7 is a flowchart of procedures performed by the sub CPU ondetecting a power-on command;

FIG. 8 is a flowchart of procedures performed by the network sub CPU ondetecting either a power-on direction or a switch-on notification;

FIG. 9 is a sequence of procedures for transition into stand-by state;

FIG. 10 is a flowchart of procedures performed by the network sub CPU ondetecting a selection of interfaces for use of data input;

FIG. 11 is a flowchart of procedures relating to notification ofinformation about a state of communication and a configuration performedby the network CPU;

FIG. 12 is exemplary criteria of step S101 in FIG. 11;

FIG. 13 is exemplary criteria of step S102 in FIG. 11;

FIG. 14 is an exemplary analytical procedure of step S104 in FIG. 11;

FIG. 15 is a flowchart of the procedures alternatively performed by themain CPU described in FIG. 11;

FIG. 16 is exemplary criteria of step S132 in FIG. 15;

FIG. 17 is a hardware configuration of a display unit according to anembodiment of a communication device of the invention;

FIG. 18 is exemplary criteria in the display unit in FIG. 17; and

FIG. 19 is a relationship between controlling CPUs and controlled CPUson power control.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the following, embodiments of the present invention will be describedwith reference to the accompanying drawings.

FIG. 1 shows a hardware configuration of a projector according to anembodiment of the invention.

The projector 100 is a projection apparatus projecting images on ascreen based on data or signals of an input image (including video inthe present specification, the same below unless it is explicitly statedotherwise). The projector 100 comprises four CPUs: a main CPU 101, a subCPU 102, a network CPU 103 and a network sub CPU 104. Each of the CPUsexecutes programs to be required and controls hardware to be required torealize the operations stated below.

The main CPU 101 operates as the main controller, which has a functionto control a Digital Mirror Device (DMD) 122 and to project an imagebased on an image signal input from either an image input 109 or thenetwork CPU 103. A DMD controller 112 directly controls the DMD 122. Themain CPU 101 may provide the DMD controller 112 with an image signal toproject and configuration data to use for projection to project arequired image on the DMD 122.

The main CPU 101 also has a signal processing function to adjustcharacteristics such as contrast, color or the like. The projectionitself may be considered as signal processing. In addition, the main CPU101 has a function to control a lamp 121 for projection of an image viaa lamp controller 111 and a fan 120 for cooling the lamp 121 via a fancontroller 110. The main CPU 101 also has a function to control adisplay 123 comprising a light-emitting diode (LED) lamp, a small liquidcrystal panel, etc., via a display controller 113 and to allow thedisplay 123 to show required information.

Furthermore, the main CPU 101 has a function to detect an operationperformed on an operating part 125 comprising buttons and switches viaan operator control 115 and a signal received by a remote controlreceiver 114, which indicates an operation on the remote controlreceiver 114. In addition to the above description, the main CPU 101 mayhandle other controls which are not handled by the other CPUs. The mainCPU 101 with the various functions operates with relatively high powerconsumption. Thus, in the stand-by state to reduce power consumption,basically the power supply to the main CPU 101 is turned off.

Second, the sub CPU 102 operates as the sub controller, which has afunction to detect an operation via the remote control receiver 114 andthe operator control 115. The sub CPU 102 also has a function to controlon/off state of power supply to the main CPU 101 and a request from thenetwork sub CPU 104 depending on a request from the main CPU 101 and thenetwork sub CPU 104. This will be described hereinafter in more detail.

Because the functions of the sub CPU 102 are substantially limited tothese functions, it operates with extremely low power consumption. Inorder to detect user's operations even in a state that power supply tothe main CPU 101 is turned off, power supply to the sub CPU 102 isalways kept on while the power is supplied from an external power sourceto a power supply unit 105.

The network CPU 103 operates as the first network controller. Thenetwork CPU 103 has a function to convert projection target data into animage signal so that the form is suitable for use by the main CPU 101,wherein the data is received from an external device via a network andthe network sub CPU 104 and is loaded from a USB memory which is anexternal storage medium connected to a Universal Serial Bus Interface(USB_I/F) 108. Also it has a function to output the transformed signalinto the main CPU 101. The workload to perform such procedures isrelatively high and thus the network CPU 103 operates with relativelyhigh power consumption.

The network CPU 104 operates as the second network controller. Thenetwork CPU 104 has a function to communicate with an external devicevia a network and pass the projection target data received from theexternal device to the network CPU 103. The projector 100 comprises awired network interface 106 for wired communication and a wirelessnetwork interface 107 for wireless communication. The former is aninterface for communication using Ethernet, and the latter is aninterface for communicating using Institute of Electrical andElectronics Engineers (IEEE) 802.11b/11a/11g/11n. The network sub CPU104 may communicate with the external device via a network using both ofor either of them.

In addition, the network sub CPU 104 has a function to control on/offstate of power supply to the wired network interface 106 and thewireless network interface 107 depending on an interface setting for useof communication. Furthermore, the network sub CPU 104 operates as asupply control part and controls on/off state of power supply to thenetwork CPU 103 depending on detection of an event indicating transitionfrom stand-by state to power on state or an event conversely indicatingfrom the power on state to stand-by state. This is described below inmore detail. Here, FIG. 19 shows a relationship between controlling CPUsand controlled CPUs on power control. In the table described in FIG. 19,the controlling CPUs are listed on the left side of the table and thecontrolled CPUs are on the upper side. For example, “main CPU” does notcontrol any CPU power. On the other hand, “sub CPU” may control the“main CPU” and “network sub CPU”. In an embodiment of the invention, asdescribed in FIG. 19, an example is described where the “sub CPU” andthe “network sub CPU” control power of other CPUs. However, in anotherembodiment of the invention, the “sub CPU” and “network sub CPU” maycontrol other CPUs unlike in FIG. 19. Alternatively, either “main CPU”or “network CPU” may control power of other CPUs in another embodimentof the invention.

A power supply unit 105 has a function to provide power from an externalpower source such as a home use electric power supply connected by powercable with each part of the projector 100. In FIG. 1, power lines forthe main CPU 101, the sub CPU 102, the network CPU 103, the network subCPU 104, the wired network interface 106 and the wireless networkinterface 107, which are main targets for power supply, are described bydashed lines. The on/off state of power supplies to at least these partsmay be changed individually. In addition, the power supply unit 105provides power to other parts which are not illustrated.

Arrows toward the power line indicate that the on/off state of powersupply though the power line may be controlled. The sub CPU 102 maycontrol on/off state of power supplies to the main CPU 101, the networkCPU 103 and the network sub CPU 104. The network sub CPU 104 may controlon/off state of power supplies to the network CPU 103, the wired networkinterface 106 and the wireless network interface 107.

The main CPU 101 and network CPU 103 may send a predetermined signal tothe power supply unit 105 to cut off power lines for themselves and turnoff the power supply (not shown). In this embodiment, the network subCPU 104 does not turn off the power supply to the network CPU 103directly, but requests it to turn off the power supply to itself. Muchthe same is true for the power supply to the main CPU 101 controlled bythe sub CPU 102. On other parts not described above, a USB_I/F 108 is aninterface to connect an external device according to a USB standard.

An image input 109 has a function to receive input of image signals froman external device according to a suitable standard such as DigitalVisual Interface Integrated (DVI-I), Video Graphics Array (VGA),RS-232C, etc. A non-volatile memory 116 is a non-volatile memory partwhich both the main CPU 101 and sub CPU 102 may access. For instance, itmay be Electrically Erasable Programmable Read-Only Memory (EEPROM). Thenon-volatile memory 116 stores an operation log, configurationinformation, etc. The configuration information may include the energysaving setting and the power on setting. The information of theconfiguration may also include interface settings for use ofcommunications, a Dynamic Host Configuration Protocol (DHCP) serversetting for network communications, a gateway address setting, etc.

A non-volatile memory 117 is a non-volatile memory part which thenetwork sub CPU 104 may access. The non-volatile memory 117 stores theconfiguration information which is referenced by at least the networksub CPU 104 during communication via a network. The content of theconfiguration information is commonly held by the non-volatile memory116 and the non-volatile memory 117 when all of the network sub CPU 104,the network CPU 103 and the main CPU 101 are working.

The content of the non-volatile memory 116 may be modified based on amodification operation which is received by the main CPU 101 from theremote control receiver 114 and operating part 125. The content of thenon-volatile memory 117 may be modified based on a modificationoperation of the protocol of the PJLink standard, which is received bythe network sub CPU 104 via a network. However, when the content of oneof the non-volatile memories is modified, the modification is reflectedin the other non-volatile memory immediately. That operation isperformed by the network sub CPU 104, the network CPU 103 and the mainCPU 101.

However, the non-volatile memory 117 does not have to maintain all ofthe content stored in the non-volatile memory 116. The projector 100works properly if it maintains configuration information of items usedby the network sub CPU 104 for communication. However, when all ofmodifiable items are maintained according to the modification operationreceived via a network, the configuration may be modified even instand-by state in which the main CPU 101 is turned off, and it mayenhance the convenience of operations.

FIG. 2 shows a functional block diagram of the network CPU 103. Asdescribed in FIG. 2, the network CPU 103 comprises a power controller201, a communication controller 202, a network sub driver 203, anoperation controller 204, a User Interface (UI) controller 205, agraphic generator 206 and a main driver 207. The power controller 201has a function to turn off the power supply to the network CPU 103itself.

The network sub driver 203 has a function relating to communication withthe network sub CPU 104. The graphic generator 206 has a function toconvert data of a projection target which is received from an externaldevice or loaded from a USB memory into an image signal. The main driver207 has a function for communication with the main CPU 101.

The control of power supply to each of the CPUs 101-104 is acharacteristic point in the projector 100. FIG. 3 shows a list of powersupply states prepared in the projector 100. As describe in FIG. 3, thepower supply states of “off”, “stand-by A” through “stand-by C”, “activestand-by”, “warming-up”, “cooling-down-down” and “on” are prepared forthe projector 100. In each state, the on/off state of power supplies tothe sub CPU 102, the network sub CPU 104, the wired network interface106, the wireless network interface 107, the main CPU 101, the lamp 121,the DMD 122, a fan 210 and the network CPU 103 are controlled asindicated in FIG. 3 respectively. Here, “low power” means that the poweris supplied only for the parts which are required to turn on in order toarchive the functions in the state, rather than being supplied for allof the CPUs. Thus, it indicates that some of functions of the CPUs arelimited but it consumes low power compared to the normal CPU operations.

As will be seen in FIG. 3, the “off” state at the top of the table isthe state in which there is no power supply from an external powersource for the power supply unit 105. That indicates the supply cable isnot connected with an outlet or is connected but the power isinterrupted. In this case, no parts can receive power supply. The “on”state at the bottom of the table is a state to fully activate theprojector 100, which is used to project an image. In this state, anymodules receive power supply and any functions are enabled. Typically,the transition to this mode occurs when the direction to switch on theprojector is detected.

In “stand-by A”, “stand-by B”, “stand-by C” and “active stand-by”states, although the power supply to the power supply unit 105 from theexternal power source is maintained, the projector 100 is not entirelyactivated but suspended with low power consumption. It is determinedwhich mode (i.e. “stand-by A”, “stand-by B”, “stand-by C” and “activestand-by”) is to be used depending on a configuration of the degree ofenergy saving, which indicates how the power is to be saved, specifiedby a user.

First, in the “stand-by A” state, the network communication function isdisabled, thus it is the state in which the power consumption is mostreduced compared to the other stand-by states. In this state, the powersupplies to the main CPU 101 and network CPU 103 with high powerconsumption as well as the network sub CPU 104 are cut off. Only thepower supply to the sub CPU 102 is maintained to detect a power-oncommand.

Second, in “stand-by B” state, only wired communication of networkcommunication is enabled. This mode is aimed to reduce energyconsumption next to the “stand-by A” state. In this case, unlike with“stand-by A” state, the power supply is turned on for the network subCPU 104 to realize network communication functions as well as the wirednetwork interface 106 to control wired communication.

Next, in “stand-by C” state, both wired and wireless networkcommunication are enabled. This mode is aimed to reduce energyconsumption next to the “stand-by B” state. In this case, in addition tothe “stand-by B” state, the power supply is turned on for the wirelessnetwork interface 107 to operate wireless network communication. In thisembodiment, a state to enable only wireless communication is notprovided; however, it may be provided. In that case, it is preferable toallow a user to configure wired or wireless communication in thestand-by state and operate based on the configuration.

Next, in “active stand-by” state, the power consumption is the highestamong the stand-by states. Fast start-up is considered in the state,thus the power supplies to the network CPU 103 and the main CPU 101 areturned on so that the projector starts projection immediately. Thus theprojection may be started soon after transition from low powerconsumption state of the main CPU 101 to normal state and lighting ofthe lamp 121.

The “warming-up” state and “cooling-down” state are temporary andtransient to transition to the other states. In the “warming-up” state,the lamp 121 is warmed so as to light it in stable condition. In the“cooling-down” state, the lamp 121 is cooled so as to turn off theprojector 100 in safety. In both states, the power is supplied for anyparts except the lamp 121 and DMD 122.

Referring to FIG. 4, the state diagram of the states described in FIG. 3for the projector 100 is shown. In the “off” state described in the topof FIG. 4, for example, the supply cable is not connected with anoutlet. The state transitions to the state corresponding to power onsetting. The power on setting specifies whether transition to the “on”state is automatically done when the power is supplied from an externalpower source (automatic) or manually done by user's power-on operation(manual).

In the automatic case, the state transitions to “on” state on the rightside via “warming-up” state. In particular, the power is supplied forthe power supply unit 105 from an external power source and then thepower is also supplied for the sub CPU 102 automatically. After that,the sub CPU 102 refers to the power on setting and recognizes the stateshould be transitioned to “warming-up” state, then it directs (includingmerely sending signals to turn on/off a switch) the power supply unit105 to enable power supply to the main CPU 101, the network sub CPU 104and the network CPU 103.

The main CPU 101 turned on by the power supply directs the power supplyunit 105 to enable power supplies to the fan controller 110 and a fan120 (not shown in FIG. 1). The network sub CPU 104 when started directsthe power supply unit 105 to enable power supplies to the wired networkinterface 106 and the wireless network interface 107. Now the statetransitions to “warming-up” state and the lamp 121 is warmed up. Inaddition, the main CPU 101 performs an initializing process for lightcontrol of the lamp 121 and image projection.

When the warming-up of the lamp 121 and the initializing process arecompleted, the main CPU 101 directs the power supply unit 105 to enablepower supplies to the lamp controller 111, the lamp 121, the DMDcontroller 112, the DMD 122(not shown in FIG. 1) and light the lamp 121to start image projection. Now the transition to “on” state iscompleted.

On the other hand, in a case where the power on setting indicates“manual” when the power cable is inserted, the state transitions from“off” state to “stand-by” state. Here, it depends on the value of theenergy saving setting as to which state of “stand-by A”, “stand-by B” or“stand-by C” the state transitions. The energy saving setting determinesthe degree of energy saving for the projector 100. The value may be“high”, “middle”, “low” or “none”.

First, when the energy saving setting is “high”, the stand-by state is“stand-by A”. The specific steps are as follows. When the power issupplied for the power supply unit 105 from an external power source, incommon with the transition to “on” state, the power supply to the subCPU 102 is automatically started. After that, the sub CPU 102 refers tothe power on setting and energy saving setting to find that it shouldtransition to “stand-by A” state, and then stands by. With thatoperation, the transition to “stand-by A” state completes and the subCPU 102 monitors a subsequent instruction (in particular, the power-oncommand).

Next, when the energy saving setting is “middle”, the stand-by state is“stand-by B”. The specific steps are as follows. When the power issupplied for the sub CPU 102 in the same manner as the case of “stand-byA”, and the sub CPU 102 finds that it should transition to “stand-by B”state, the sub CPU 102 directs the power supply unit 105 to enable powersupplies to the network sub CPU 104 and the network CPU 103.

Then, the network sub CPU 104 started by the power supply refers to theenergy saving setting and finds it should transition to “stand-by B”state. The network sub CPU 104 directs the power supply unit 105 toenable power supply to the wired network interface 106 but disable powersupply for the network CPU 103. After that, the network sub CPU 104performs an initializing process required for starting communication,and completes the transition to “stand-by B” state. In this state,monitoring of power-on command via a wired network or modification ofsettings of the projector 100 via the wired network may be done inaddition to the case of “stand-by A” state. Although the power issupplied for the network CPU 103, the supply is stopped immediately andthe CPU 103 does not perform any operations.

Next, when the energy saving setting is “low”, the stand-by state is“stand-by C”. The specific steps are as follows. In addition to thesteps of the above “stand-by B” state, the network sub CPU 104 directsthe power supply unit 105 to enable power supply to the wireless networkinterface 107 and then it performs an initializing process required forstarting communication. In this state, monitoring of power-on commandvia a wireless network or modification of settings of the projector 100via the wireless network may be done in addition to the case of“stand-by B” state.

Next, when the energy saving setting is “nothing”, the stand-by state is“active stand-by”. The specific steps are as follows. When the sub CPU102 finds that it should transition to “active stand-by” state, itdirects the power supply unit 105 to enable power supply to the main CPU101. The main CPU 101 refers to the energy saving setting and finds itstarts due to the “active stand-by” state, and then it starts with lowpower and performs the initializing process except lighting the lamp 121and image projection.

Also, when the network sub CPU 104 refers to the energy saving settingto find that it should transition to “active stand-by” state, the powersupply to the network CPU 103 from the power supply unit 105 is notturned off but kept on. As a result, the network CPU 103 also starts andit performs the required initializing process. After that, thetransition to “active stand-by” state completes.

In the state, a start-up process for the main CPU 101 and the networkCPU 103 on transition to “on” state is not required so that thetransition may complete in a short time. In any stand-by states, thestate transitions to “on” state via “warming-up” state on detection ofthe power-on command. The power-on command may be invoked by anoperation of the power-on key on the projector 100 which is included inthe operating part 125, an operation of the power-on button on a remotecontroller, a “PON” command from a control terminal (not shown), arequest of power-on from a PJLink application or external linkapplication via a network.

The sub CPU 102 detects the command from the power-on key, the remotecontroller or the control terminal and conveys it to the network sub CPU104. The command sent via a network is detected by the network sub CPU104. When the sub CPU 102 detects the power-on command and the state is“stand-by A” (i.e. the power supply to the network sub CPU 104 is turnedoff), the sub CPU 102 directs the power supply unit 105 to enable thepower supply to the network sub CPU 104. In any stand-by state, itnotifies the network sub CPU 104 of receipt of the power-on command.

In any case, when the network sub CPU 104 receives the notification ordetects the power-on command by itself, it directs the sub CPU 102 toenable the power supply to the main CPU 101 (in case of “activestand-by” state, it directs the sub CPU 102 to transition from low powerstate to normal state).

When the sub CPU 102 receives the direction, in common with the abovecase of transition to “warming-up” state, it directs the power supplyunit 105 to turn on the power supply to the main CPU 101. Also, thenetwork sub CPU 104 directs the power supply unit 105 to turn on thepower supply to the network CPU 103 (unnecessary in case of “activestand-by” state). As a result of the process, the network CPU 103 isstarted. When there is a network interface such that the power supply isoff state, the network sub CPU 104 directs the power supply unit 105 toturn on the power supply.

After the above operations, each part finishes the required initializingprocess and transitions to “warming-up” state, and then transitions to“on” state in common with the case after the transition from “off” stateto “warming-up” state. Here, receipt of projection data from a networkor detection of connection of a USB memory into the USB_I/F 108 may beused as a trigger to transition from a stand-by state to “on” state.That results in improvement of usability as the state of the projector100 can transition to “on” state by providing data required forprojection without any user operation of the power switch. Here, in“active stand-by” state, the network CPU 103 can detect the condition ofthe USB_I/F 108. In order to detect it even in the other state, theprojector 100 may be configured so that the network sub CPU 104 detectsit.

Here, the steps performed by the sub CPU 102 and the network sub CPU 104are described with flowcharts in order to transition to the abovestand-by states and “on” state. Referring to FIG. 5, the steps performedby the sub CPU 102 on start-up are described. The power supply to thepower supply unit 105 from an external source is turned on, and thepower supply to the sub CPU 102 is started, then the steps described inFIG. 5 are executed after the required initializing process.

In the steps, the sub CPU 102 refers to the power on setting and energysaving setting (S11, S12). If the power on setting indicates“automatic”, the sub CPU 102 determines that it should transition to“on” state and it directs the power supply unit 105 to turn on the powersupplies to the network sub CPU 104, the network CPU 103 and the mainCPU 101, and then finishes the steps. On the other hand, if the power onsetting indicates “manual” and energy saving setting indicates“nothing”, the sub CPU 102 determines that it should transition to“active stand-by” state and it directs the power supply unit 105 to turnon the power supplies to the network sub CPU 104, the network CPU 103and the main CPU 101 (S13).

If the power on setting indicates “manual” and energy saving settingindicates “low” or “middle”, the sub CPU 102 determines that it shouldtransition to “stand-by B” or “stand-by C” state and it directs thepower supply unit 105 to turn on the power supplies to the network subCPU 104 and the network CPU 103 (S14).

If the power on setting indicates “manual” and energy saving settingindicates “high”, the sub CPU 102 determines that it should transitionto “stand-by A” state and finishes the steps.

Referring to FIG. 6, a flowchart performed by the network sub CPU 104 onits start-up is described. When the power supply to the network sub CPU104 from power supply unit 105 is started, the steps described in FIG. 6are executed after the required initializing process.

In the steps, the network sub CPU 104 refers to the power on setting andenergy saving setting (S21, S22). If the power on setting indicates“automatic”, the network sub CPU 104 determines that it shouldtransition to “on” state and it directs the power supply unit 105 toturn on the power supplies to the wired network interface 106 and thewireless network interface 107 (S24). After that, the network sub CPU104 performs the initializing process of the network interface started(S25), and finishes the steps. In that case, the power supply to thenetwork CPU 103 is kept on, and that state is turned on at step S13 inFIG. 5.

If the power on settings indicates “manual” and energy saving settingsindicates “nothing”, the network sub CPU 104 determines that it shouldtransition to “active stand-by” state and it directs the power supplyunit 105 to turn on the power supplies to the wired network interface106 and the wireless network interface 107 (S24). In this case, thepower supply to the network CPU 103 is kept on, that state is turned onat the step S13 in FIG. 5.

If the power on settings indicates “manual” and energy saving settingsindicates “low”, the network sub CPU 104 determines that it shouldtransition to “stand-by C” state. In this case, the network sub CPU 104directs the power supply unit 105 to turn off the power supply to thenetwork CPU 103 which should have been turned on (S23). After that, incommon with the above case, the network sub CPU 104 turns on the powersupplies to the wired network interface 106 and wireless networkinterface 107 (S24) and then it performs the initializing process (S25).

If the power on settings indicates “manual” and energy saving settingsindicates “middle”, the network sub CPU 104 determines that it shouldtransition to “stand-by B” state. In this case, the network sub CPU 104directs the power supply unit 105 to turn off the power supply to thenetwork CPU 103 (S26) which should have been turned on by the sub CPU104 at the step S14 in FIG. 5. After that, the network sub CPU 104directs the power supply unit to turn on the power supply to the wirednetwork interface 106 and to turn off the power supply to the wirelessnetwork interface 107 (S27). The network sub CPU 104 performs theinitializing process of the started network interface (e.g. the wirednetwork interface 106 only) (S25), and finishes the steps. When thepower on settings indicates “manual” and energy saving settingsindicates “high”, the state is supposed to transition to “stand-by A”state on the connection of the power cable, thus the network sub CPU 104could not start. Therefore, any steps for that case are not describedhere.

Referring to FIG. 7, a flowchart performed by the sub CPU 102 when itdetects a power-on command is described. When the sub CPU 102 detectsthe power-on command in any stand-by states as described above, itexecutes the steps in FIG. 7.

At first, the sub CPU 102 refers to the energy saving setting (S31), andif the setting indicates “high”, it directs the power supply unit 105 toturn on the power supply to the network sub CPU 104 (S32). This isbecause the present state is “stand-by A” and the network sub CPU 104 isnot supposed to be started. In any case (waiting for the start-up of thenetwork sub CPU 104 follows the step S32), the sub CPU 102 notifies thenetwork sub CPU 104 of the power-on (S33), and then finishes the steps.

Referring to FIG. 8, a flowchart performed by the network sub CPU 104when it detects a power-on command or switch-on notification isdescribed. When the network sub CPU 104 detects the power-on command inany stand-by states as described above or the switch-on notificationtransmitted at step S33 in FIG. 7, it executes the steps in FIG. 8.

First, the network sub CPU 104 directs the sub CPU 102 to turn on thepower supply to the main CPU 101 (S41). Responding to the direction, thesub CPU 102 directs the power supply unit 105 to turn on the powersupply to the main CPU 101 (not shown in FIG. 1). That is, the networksub CPU 104 triggers to turn on the power supply to the main CPU 101.

Next, the network sub CPU 104 directs the power supply unit 105 to turnon the power supply to the network CPU 103 (S42). After that, thenetwork sub CPU 104 refers to the energy saving setting and determinesthe current stand-by state (S43), and starts network interfaces whichhave not started yet depending on the state. When the energy savingsetting indicates “middle”, the current state is “stand-by B” state. Inthis case, as the wireless network interface 107 is not started, thenetwork sub CPU 104 directs the power supply unit 105 to turn on thepower supply to the wireless network interface 107 (S44) and performsits initializing process (S45). When the energy saving setting indicates“high”, the current state is “stand-by A” state. In this case both ofthe wired network interface 106 and the wireless network interface 107are not started, so the network sub CPU 104 directs the power supplyunit 105 to turn on the power supplies to them (S46) and performs theirinitializing process (S45). When the energy saving setting indicates“nothing” or “low”, no step is performed here. After that, the networksub CPU 104 finishes the steps in any case.

On the projector 100, the sub CPU 102 and the network sub CPU 104perform the above steps respectively and thereby the state maytransition from the “off” state to “on” state directly or indirectly viathe one of stand-by states. On the transition from “active stand-by” to“on” state, the network sub CPU 104 notifies the main CPU 101 via thenetwork CPU 103 to transition to “on” state, and then the main CPU 101starts the fan 120, lamp 121 and DMD 122. These operations are notdescribed in FIG. 5 to FIG. 8.

Referring to FIG. 4 again, the state of the projector 100 transitions toa stand-by state via a cooling-down state when the projector in “on”state detects an instruction for transition to stand-by state (power-offcommand). The state to be transitioned to is determined depending on theenergy saving setting in common with the connection of the power cable.The power-off command may be invoked by an operation of the power-on keyon the projector 100 which is included in the operating part 125, anoperation of the power-on button on a remote controller, a “POF” commandfrom a control terminal (not shown), a request of power-off from aPJLink application or external link application via a network.

The main CPU 101 detects the command from the power-on key, the remotecontroller or the control terminal. The command sent via a network isdetected by the network CPU 103 based on the data which it receives fromthe network sub CPU 104. Any information is gathered into the main CPU101 once. After showing a confirmation display if desired, the steps totransition from cooling-down state to stand-by state are performed.

FIG. 9 shows a sequence to transition to the stand-by state. Fortransition to “active stand-by”, description is skipped because it isenough for the main CPU 101 merely to stop the fan 120, the lamp 121 andthe DMD 122 and transition to a low power consumption mode. Asillustrated in FIG. 9, when the main CPU 101 detects a power-off command(S51), it notifies the network CPU 103 of transition to a stand-bystate. Responding to that, the network CPU 103 transmits a transitionrequest to stand-by to the network sub CPU 104.

On the receipt of the transition request to stand-by, the network subCPU 104 starts steps to turn off power supply to each part of theprojector 100. First, the network sub CPU 104 directs the network CPU103 to turn off the power (S54). When the network CPU 103 receives thedirection, it performs the required shutdown operation (S55) and directsthe power supply unit 105 to turn off the power supply to itself. Thereason why the network sub CPU 104 does not direct the power supply unit105 to turn off the power supply to the network CPU 103 directly is toavoid failure caused by sudden stoppage of the network CPU 103. Thus thedirection at step S54 is a trigger to turn off the power supply to thenetwork CPU 103.

In a case where the degree of power saving (i.e. the energy savingsetting) is “middle”, the network sub CPU 104 directs the power supplyunit 105 to turn off the power supply to the wireless network interface107, wherein the supply is turned off on “stand-by B” state. In a casewhere the degree of power saving is “low”, the network interface neednot to be stopped. In a case where the degree of own saving is “high”,no step is described here because the network sub CPU 104 itself isstopped later. However, it may be stopped here.

Next, the network sub CPU 104 requests the sub CPU 102 to turn off thepower of the main CPU 101 (S59). On receipt of the request, the sub CPU102 directs the main CPU 101 to turn off the power (S60). When the mainCPU 101 receives the direction, it performs the required shutdownoperation (S61) and then directs the power supply unit 105 to turn offthe power supply to itself (S62).

The shutdown operation at step 61 includes cooling of the lamp 121.During the cooling, the state becomes “cooling-down” state. Or, the mainCPU 101 may perform the cooling before step S52. The reason why thenetwork sub CPU 104 does not direct the power supply unit 105 to turnoff the power supply to the main CPU 101 directly is to avoid failurecaused by sudden stoppage of the main CPU 101. Thus the request at stepS59 is a trigger to turn off the power supply to the main CPU 101.

Next, the sub CPU 102 refers to the setting of the degree of the powersaving (i.e. the energy saving setting), and when it indicates “high”,the sub CPU 102 directs the network sub CPU 104 to turn off the power.On receipt of the direction, the network sub CPU 104 performs therequired shutdown operation (S65) and then directs the power supply unit105 to turn off the power supply to itself (S66). The shutdown operationat step 65 includes stopping the power supply to a network interface towhich the power is supplied.

When the degree of energy saving (energy saving setting) is either “low”or “middle”, stoppage of the network sub CPU 104 is not required, andthus the sequence finishes. On the projector 100, each CPU performs theoperations respectively, and thereby the transition from “on” to one ofthe stand-by states as described in FIG. 4 is done. Here, the order ofsteps S54, S57 to S59, performed by the network sub CPU 104 is notlimited to that as described in FIG. 9.

Referring back to FIG. 4, on the projector 100, the power cable may beunplugged to stop the power supply to the power supply unit 105. When itoccurs in a stand-by state or “on” state, the state of the projector 100transitions to “off” state because it cannot be powered on due to thelack of the power supply. It is not officially permitted to unplug thepower cable in “warming-up” state or “cooling-down” state even althoughit is possible.

As described above, on the projector 100, the four CPUs—main CPU 101,sub CPU 102, network CPU 103 and network sub CPU 104—are arranged toturn on/off their own power supplies to each CPU and thereby thedetailed control for power consumption is achieved. In particular, apart which is powered may be configurable by a user based on the energysaving setting so that the power consumption in a stand-by state may beminimum and suitable for the user's intended purpose.

The network sub CPU 104 as a CPU for handling network communication andthe network CPU 103 to deal with high load data operations are arrangedseparately, and in a stand-by state, basically only the network sub CPU104 is powered. That decreases power consumption in a stand-by statewhile the network communication is enabled in the stand-by state.

Also, various kinds of power states may be arranged in addition to thestates described in FIG. 3 and FIG. 4 on the projector 100, and they maybe used depending on various kinds of triggers and settings. Forexample, even during projection in “on” state, the power supply for thenetwork CPU 103 may be turned off when data input from an externaldevice via a network has not been detected for a predetermined timeperiod.

As the network CPU 103 need not perform image processing duringprojection by image signal input from the image input 109, powerconsumption in “on” state may be reduced to stop the power for it. Inthat case, the network sub CPU 104 may control the power by performingsteps S54 to S56 in FIG. 9.

The network sub CPU 104 is suitable for monitoring data receptionbecause it controls network communication, thus the networkcommunication function itself is kept enabled by the network sub CPU104.

Furthermore, when the network CPU 103 detects data input to be convertedinto an image signal from an external device via a network while thenetwork CPU 103 stops, the network sub CPU 104 may direct the powersupply unit 105 to turn on the power supply to the network CPU 103. Inthat case, the step is performed in common with S42 in FIG. 8. As aresult, if any data operation for data received via a network isrequired, the network CPU 103 may handle it immediately.

The power supply to each part may be controlled based on a selection ofinterface for data input in a stand-by state or “on” state (e.g.selection of either receiving target data for projection via a networkor input the data from the image input 109). Or network interfaces to beused may be selected (e.g. either wired or wireless or both of them).The selection is made through an operation part, a remote controller orconfiguration performed via a network. In any method, the selection maybe reported to the network sub CPU 104.

FIG. 10 shows a flowchart performed by the network sub CPU 104 when theselection of interface for data input is detected. When the selection isdetected, the network sub CPU 104 starts the steps in FIG. 10. At first,the network sub CPU 104 determines whether the selection indicatesnetwork communication is used (S71). Then, if the network communicationis used, as well as the step S42 in FIG. 8, the network sub CPU 104directs the power supply unit 105 to turn on the power supply to thenetwork CPU 103 (S72). When the power supply has turned on, thedirection may not be done. Or if the network communication is not used,as well as steps S54 to S56 in FIG. 9, the network sub CPU 104 directsthe network CPU 103 to turn off the power (S73). Also, when the powersupply has been turned off, the direction may not be done.

After both cases, the network sub CPU 104 directs the power supply unit105 to turn on the power supply to the network interface to be usedbased on the selection and to turn off the network interface not to beused (S74). The network sub CPU 104 performs the initializing processfor the newly started network interface (S75), and then finishes thesteps.

For the aforementioned steps, the network CPU 103 may be automaticallyturned off in case the function is not used and thereby the powerconsumption may be decreased. Also, as a network interface which is notused may be stopped, the power consumption may be decreased regardlessof whether the state is stand-by or “on”.

The operation on the projector 100 when the power supply to the networkCPU 103 is started is described below. On the projector 100, asdescribed above, the settings may be externally modified by function ofthe network sub CPU 104 even when the network CPU 103 or main CPU 101 isnot turned on.

In that case, the display does not work and thereby the user cannotrealize the modification of the settings. That is, during directoperation for the projector 100, the settings may be modified while userdoes not realize it. Also in case that the network CPU 103 or the mainCPU 101 is turned off, the network sub CPU 104 may communicate with anexternal device via a network to change conditions of the communication.For example, reduction of wireless signal strength interruptscommunication for an access point or a network defect blocks networkcommunication.

The projector cannot notify a user of an occurrence of such event, andthus she directly operates the projector unconscious of the change ofthe conditions. Thus, at the point of start-up of the network CPU 103,the projector may notify the user of information about a state ofcommunication and the required information about a configuration. Forthat operation, if an unexpected event changes the condition in astand-by state, a user may know the change of the condition and thesettings when she executes the main function of the projector 100.

Notification is done when the network CPU 103 is turned on, that is, itis done when the state transitions to “on” state. Thus, the main CPU 101may perform the process of the notification on the start-up as describedlater. In addition, as described above, when the network CPU 103 startsor stops regardless of transition to “on” state or stand-by state, theoperation relating to the notification may be done after confirming thatthe start-up is caused by the transition to “on” state or may beperformed by the main CPU 101.

FIG. 11 shows a flowchart of operations relating notification ofinformation about a state of communication and a setting, which isperformed by the network CPU 103. When the network CPU 103 receives thepower supply and finishes the required initializing process, the networkCPU 103 starts the steps in FIG. 11.

First, the network CPU determines whether the projector 100 is in thecondition that it may display the information relating to thenotification (S101). The information cannot be displayed in case themain CPU 101 controlling the display is not started. Much informationcannot be displayed in case the lamp 121 and DMD 122 don't work. Thusthe determination may be based on the criteria illustrated in FIG. 12which are based on conditions of power supply to each part.

In FIG. 12, “LED only” indicates that only a lamp in the display 123 isavailable. It is not enough to display working conditions and settingsand thus the projector is “unable to display” them. However, it may beenough to display an incidence of network error or simple information.In that case, the network CPU 103 may determine that the projector is“enabled to display” them.

A combination of “on” and “off” which is impossible in theaforementioned operation is described in FIG. 12. If the memory hasenough room for storing a table like that, all of the combinations maybe stored in it for future extension. Much the same is true of thefollowing tables.

When the network CPU 103 determines “enabled to display” at step S101,it determines whether information about a state of network communicationand a configuration may be obtained. Here, the communication state andthe information of the configuration may not be obtained when thenetwork sub CPU 104 does not work. If each network interface does notwork, the interface may not obtain the information (however, theinformation of the configuration may be obtained by the network sub CPU104). They may be used for the determination. The determination may bedone based on criteria depending on a state of power supply to each partillustrated in FIG. 13 (illustrative only). In case the informationabout a state of communication needs to be displayed but the state is“Obtainable (setting only)”, the network CPU 103 determines “Notobtainable”.

If the network CPU 103 determines “Obtainable” at step S102, it obtainsinformation about a state of network communication and a configurationfrom the network sub CPU 104 (S103) and analyses them (S104). Based onthe result, the network CPU 103 determines whether information to bereported to a user exists (S105). If so, the network CPU 103 gives theinformation to the main CPU 101, requests the main CPU 101 to display(S106), and then finishes the steps. At step S103, the network CPU 103does not have to obtain all information administered by the network subCPU 104, but may obtain information for which display and analysis arepossible. In case some of network interfaces don't work, the network CPU103 may obtain information on working network interfaces.

If the network CPU 103 determines “no” at step S101, S102 or S105, itfinishes the steps. The main CPU 101 which receives the request at stepS106 controls the DMD 122 and the display 123 to display the informationand notify the user. Or the notification may be displayed on an externaldevice of the user by sending the notification to the external devicevia a network.

FIG. 14 shows an exemplary analysis method at step S104. In thisanalysis, the network CPU 103 determines whether the projector isconfigured to use a network for image input (S111). If not, because itis useless to show network condition or configuration information, thenetwork CPU 103 determines that no information exists to be displayed(S121) and finishes the analysis. Alternatively, the message indicatinga network is not used may be displayed.

If the network CPU 103 determines that the projector is configured touse the network at step S111, it further determines which is selectedeither a wired network or a wireless network (S112, S113). When both ofthem are selected, it is substantially similar to not using the network,thus the network CPU 103 determines no information exists to bedisplayed (S121) and finishes the analysis. If either of them isselected at step S112 or S113, the network CPU 103 determines whether anetwork connection setting has been done (S114). If not, the network CPU103 determines such condition should be displayed so that the user canunderstand that the setting process is ongoing (S122), and finishes theanalysis.

If the setting has been done at step S114, the network CPU 103determines whether DHCP is enabled (S115). If enabled, the network CPU103 determines whether it can connect with a DHCP server (S116). If not,the network CPU 103 determines such condition should be displayedbecause the user can understand that the projector cannot connect withthe DHCP server (S123), and finishes the analysis. If the network CPU103 determines that it can connect with the DHCP server, it furtherdetermines that such condition should be displayed so that the user canunderstand that the projector is connected to network (S124) andfinishes the analysis.

If DHCP is not enabled at step S115, the network CPU 103 determineswhether a host using the identical IP address with the projector existson the network. If such host exists (Yes at S117), the network CPU 103determines that such condition should be displayed so that the user canunderstand that a host using the identical IP address exists (S125) andfinishes the analysis. If such host does not exist at the step S117, thenetwork CPU 103 determines whether it can connect with a gateway (S118).If it can connect with the gateway (Yes at S118), the network CPU 103determines that such condition should be displayed so that the user canunderstand that the projector is connected to a network (S124), andfinishes the analysis.

If it cannot connect with the gateway, the network CPU 103 determinesthat such condition should be displayed so that the user can understandthat the projector cannot connect with the gateway (S126), and finishesthe analysis. It will be appreciated that the network CPU 103 maydetermine which part of settings obtained depending on communicationstatus is displayed.

For the steps performed by the network CPU 103, in case a configurationor a state of communication of the projector 100 is changed while theycannot be displayed, the user can recognize the condition after thedisplay becomes available. If the main CPU 101 is not started andthereby it is not able to display or the network sub CPU 104 is notstarted and thereby the required information cannot be obtained, thedisplay or analysis is not performed. That results in reduction ofuseless operation and workload.

Although the power supply to the network CPU 103 is kept on when thestate transitions from “active stand-by” to “on”, the network CPU 103may similarly perform the steps in FIG. 11. The notification of the usermay be done by, unlike the aforementioned projection or light pattern,display on an LCD panel or by voice output with a speaker when theprojector comprises such hardware.

As stated above, The main CPU 101 can perform the steps in FIG. 11. FIG.15 shows a flowchart of such a case. When the power supply to the mainCPU 101 is started and the required initializing process is done, themain CPU 101 starts the steps in FIG. 15. In case the state transitionsfrom “active stand-by” to “on” state, the same steps are performed.

The main CPU 101 determines whether the projector 100 is in a state inwhich the information relating to the notification may be displayed(S131). The criteria for the determination may be the same as step S101in FIG. 11. If the information may be displayed, the main CPU 101determines whether information about a state of network communicationand a configuration is obtainable (S132). In order to request thenetwork CPU 103 to obtain the information from the network sub CPU 104,the main CPU 101 considers the state of the network CPU 103. That is,the main CPU 101 determines the information is not obtainable if thenetwork CPU 103 does not work. The main CPU 101 determines based on acriteria in FIG. 16 depending on a state of power supply to each part.

If the main CPU 101 determines obtainable at step S132, it requests thenetwork CPU 103 to send the information about a state of networkcommunication and a configuration, and obtains them (S133). When thenetwork CPU 103 receives the request, it obtains the requiredinformation from the network sub CPU 104 and sends it to the main CPU101. The main CPU 101 analyzes the information which is obtained at thestep S133 (S134), and thereby it determines whether information to bereported to the user exists (S135). If so, the main CPU 101 displays itby projection or LED (S136), and then finishes the steps. The analysisat step S134 may be the same as that of step S104 in FIG. 11.

In the steps described above, as well as the case where the network CPU103 performs the steps, if the configuration or state of communicationis changed while if cannot be displayed, the user can recognize thestate or setting changed soon after it becomes available on the display.

With that, the description about embodiments of the invention is ended.In the invention, a specific arrangement of each part, an operation, acommunication protocol used and information displayed are not limited bythe description. For example, in the embodiment stated above, currentinformation about a state of communication or a configuration of theprojector 100 is displayed at the steps in FIG. 11 and FIG. 15. However,the information about a state of communication or a configuration at thetime when the power supply to main CPU 101 was turned off and the statetransitioned to a stand-by state may be stored in a recording medium onshut-down procedure. When the state becomes “on”, it may be comparedwith the information obtained from the network sub CPU 104, and if theyare not identical (i.e. they are changed), the user may be notified ofthe information.

Mere existence of the change may be reported by a simple display devisesuch as an LED. Confirming the change, a user can investigate the causeif needed. Or when the information about a configuration or a state ofcommunication is not changed, it may be less necessary to report it.Therefore, by adopting the aforementioned method, the notification maybe effectively done depending on the situation.

In FIG. 5 and FIG. 6, when the state transitions from “off” to “stand-byB” or “Stand-B C”, the sub CPU 102 directs the network CPU 103 to turnon the power, and then the network sub CPU 104 directs to turn it off.However, in that case, the sub CPU 102 may not direct the network CPU103 to turn on the power while the network sub CPU 104 may not direct tochange the power supply state (i.e. “off” state of the power supply iskept).

In addition to the projector 100, this invention may be applied to anycommunication device which communicates with an external device via anetwork.

For example, it can be applied to a display device 100′ in FIG. 17. Thedisplay device 100′ comprises a liquid crystal panel 141, a speaker 142,and a LED 143; and a panel controller 131, a speaker controller 132 anda LED controller 133 corresponding to them in place of the fan 120, thelamp 121, the DMD 122, the display 123 and the controllers of theprojector 100. The display device 100′ can use criteria in FIG. 18 forthe determination at steps S101 and S131 in FIG. 11 and FIG. 15

Furthermore, this invention may be applied to network-enabled consumerelectronics, vending machines, medical devices, electric power units,air intake systems, measuring systems for gas, water or electricservice, cars, aircraft or communication devices of general purposecomputers.

The program according to the invention causes each of the CPUs in theaforementioned communication device to realize the function. The programis performed by a computer to achieve effects as described above. Suchprogram may be stored in ROM arranged in a computer in advance or arecording medium such as a CD-ROM, flexible or the like disk or anon-volatile storage medium (memory) such as NVRAM, EEPROM, memory cardor the like. The stored program in the memory may be installed into acomputer and executed by a CPU to perform the steps as stated above.

Alternatively the program can be downloaded from a network-connectedexternal device comprising a record medium which stores the program orstoring the program in a recording device. It will be appreciated thatconstitution of the embodiments, examples and alternatives can bearbitrarily combined and practiced unless they conflict.

Further, the present invention is not limited to these embodiments, butvarious variations and modifications may be made without departing fromthe scope of the present invention.

The present application is based on Japanese Priority Application No.2012-209242 filed on Sep. 24, 2012 and No. 2012-002346 on Jan. 10, 2012with the Japanese Patent Office, the entire contents of which are herebyincorporated by reference.

What is claimed is:
 1. A communication device, comprising: a maincontrol part configured to receive and process an image signal; a firstnetwork control part configured to convert data input from an externaldevice into the image signal and provide the main control part with theimage signal; a sub control part configured to detect a power-oncommand; and a second network control part configured to controlcommunication with the external device via a network to provide thefirst network control part with data input from the external device;wherein power supplies to the main control part, the sub control part,the first network control part and the second network control part areindependently controlled.
 2. The communication device as claimed inclaim 1, wherein the second network control part includes a supplycontrol part configured to control power supply to the first networkcontrol part.
 3. The communication device as claimed in claim 2, whereinthe supply control part is configured to turn off the power supply tothe first network control part when no data input from the externaldevice via the network has been detected for a predetermined timeperiod.
 4. The communication device as claimed in claim 3, wherein thesupply control part is configured to turn on the power supply to thefirst network control part upon detecting data input that is to beconverted into the image signal and that is supplied from the externaldevice via the network.
 5. The communication device as claimed in claim2, wherein the supply control part is configured to turn off the powersupply to the first network control part when an interface part, whichaccepts a direction of whether communication with the external device isused via the second network control part, accepts the direction that thecommunication is not used.
 6. The communication device as claimed inclaim 2, further comprising an connection detecting part configured todetect connection of a storage medium to the communication device,wherein the supply control part is further configured to: control thepower supply to the main control part; and turn on the power supplies tothe first network control part and the main control part when theconnection detecting part detects the connection of the storage medium.7. The communication device as claimed in claim 1, wherein the maincontrol part includes: an information managing part configured to manageactivity log and configuration information of the communication device;and a recording part configured to cause the second network control partto record at least part of the activity log and configurationinformation.
 8. The communication device as claimed in claim 1, furthercomprising a plurality of communication interfaces configured tocommunicate with the external device via the network, wherein the secondnetwork control part includes a supply control part configured tocontrol power supply to each of the communication interfaces, and thesupply control part turns off the power supply to a communicationinterface which is not used for communication in response to a selectionwhich is accepted by a third interface part, where the third interfacepart is configured to accept a selection of a communication interfacewhich is used for communication.
 9. The communication device as claimedin claim 1, further comprising a notification part configured to, whenpower supply to the first network control part is turned on, obtaininformation about a state of communication with the external device or aconfiguration for communication with the external device from the secondnetwork control part and perform notification of all or part of theinformation externally.
 10. The communication device as claimed in claim1, further comprising a memory part configured to store informationabout a state of communication with the external device or aconfiguration for communication with the external device as exists inthe second network part at the time the power supply to the firstnetwork control part is turned off, wherein the first network controlpart has a notification part configured to, when the power supply to thefirst network control part is turned on, determine whether informationabout a state of communication with the external device or aconfiguration for communication with the external device as exists inthe second network part is different from the information stored in thememory part, and when the information is different, report thedifference externally.
 11. The communication device as claimed in claim9, wherein the first network control part causes the main control partto perform the notification, and the first network control part refrainsfrom obtaining the information about a state of communication with theexternal device or a configuration for communication with the externaldevice from the second network part when the power supply to the firstnetwork control part is turned on but the power supply to the maincontrol part is turned off.
 12. The communication device as claimed inclaim 9, wherein the first network control part refrains from obtainingthe information about a state of communication with the external deviceor a configuration for communication with the external device from thesecond network part when the power supply to the first network controlpart is turned on but the power supply to the second network controlpart is turned off.
 13. The communication device as claimed in claim 9,further comprising a plurality of communication interfaces configured tocommunicate with the external device via the network, wherein the secondnetwork control part has a supply control part configured to controlpower supply to each of the communication interfaces, and when the firstnetwork control part obtains the information about a state ofcommunication with the external device or a configuration forcommunication with the external device from the second network part, thefirst network control part obtains information relating to acommunication interface of the plural communication interfaces whosepower supply is turned on.
 14. The communication device as claimed inclaim 1, further comprising a notification part configured to, when thepower supply to the main control part is turned on, obtain informationabout a state of communication with the external device or aconfiguration for communication with the external device from the secondnetwork control part and report all or part of the information.
 15. Thecommunication device as claimed in claim 1, further including a memorypart configured to store information about a state of communication withthe external device or a configuration for communication with theexternal device as exists in the second network part at the time thepower supply to the main control part is turned off, wherein the maincontrol part has a notification part configured to, when the powersupply to the main control part is turned on, determine whetherinformation about a state of communication with the external device or aconfiguration for communication with the external device as exists inthe second network part is different from the information stored in thememory part, and when the information is different, report thedifference externally.
 16. A control method for a communication devicecomprising: a main control part configured to receive and process animage signal; a first network control part configured to convert datainput from an external device into the image signal and provide the maincontrol part with the image signal; a sub control part configured todetect a power-on command; and a second network control part configuredto control communication with the external device via a network toprovide the first network control part with data input from the externaldevice; wherein power supplies to the main control part, the sub controlpart, the first network control part and the second network control partare independently controlled, the control method including obtaininginformation about a state of communication with the external device or aconfiguration for communication with the external device from the secondnetwork control part when power supply to the first network control partor the main control part is turned on; and reporting all or part of theinformation to a user.
 17. A computer-readable storage medium forstoring a program therein, the program causing a communication device,which includes a main control part configured to receive and process animage signal; a first network control part configured to convert datainput from an external device into the image signal and provide the maincontrol part with the image signal; a sub control part configured todetect a power-on command; and a second network control part configuredto control communication with the external device via a network toprovide the first network control part with data input from the externaldevice; wherein power supplies to the main control part, the sub controlpart, the first network control part and the second network control partare independently controlled, to execute a control method, the methodcomprising: obtaining information about a state of communication withthe external device or a configuration for communication with theexternal device from the second network control part when power supplyto the first network control part or the main control part is turned on;and reporting all or part of the information to a user.